I'm trying to use the inputs on my Motu Ultralite to route stuff into LiSa, but I'm having problems. I seem to be able to use the first mic input (tried it with my guitar) by specifying --adc4 on the command line (I guessed that adc numbers match the dac numbers that I see with chuck --probe).

Then I tried one of the stereo inputs, and that doesn't sound so nice. Here's the source code that I'm experimenting with:

which I guess means that I have to specify the amount of inputs if I want to use adc.chan(2) in the program. I am attaching samples of what the original sound source and the result when dragged through ChucK (recorded with a mic next to a noisy PC box) sounds like. They were recorded simultaneously.

I get the impression that something is wrong with the data format, like 16 bits are sent but 8 are expected, or something like that. Do you agree?

I can't be the first one to try out mulitple inputs into ChucK like this... I remember I had similar problems when trying out multiple outputs - that was a matter of trial and error to find the correct argument (--out8 even though chuck --probe tells me my sound interface has 14 outputs). I've tried the settings that I could think, now I'm starting to feel like I'm clutching at straws. Any ideas?

OK, like the last time, it payed of to write a post here, think some more and then try something stupid like adding --out8 to the command line and see what happened. The output no longer comes to the main ultralite output, rather the first numbered output, but anyway it works!

I think this should be enough for my purposes - but a little annoying. Don't y'all ever run into these things with your sound interfaces? Feels like black magic...

I think this should be enough for my purposes - but a little annoying. Don't y'all ever run into these things with your sound interfaces? Feels like black magic...

No, I don't. My EMU 1616m has been vary stable and predictable with ASIO ChucK; outputs just use it's virtual ASIO busses, starting at 1 and I've used it up to 6 outs. I should mention the EMU doesn't make a distinction between "main" and "numbered" outputs like your card does, instead it can offer a number of ASIO and WM channels to applications and those can be routed to physical outputs or to -for example- WM inputs that can be send to another program.

I can't remember ever having issues with inputs but than again; I don't think I ever tried using more then two of those either.

Thought for a moment that Plork was using Motu interfaces but it turns out they use Edirol. Hmmmm. And the results of --probe look very healthy as well.

Did you verify that using this mic on this input does work well when recording to -say- Audacity?_________________Kassen

The Motu works pretty much as it's supposed to with Ableton Live, I use multiple ins and outs pretty often. Funny you should mention Audacity, because that one also has problems, though those are usually that I get silence after I select one input, then when I record, stop record and try to record again it seems to have forgotten about my input setup. I figured it was a general Audacity issue on OSX, but maybe it's stuff like this that make people whine about their Motu gear every now and then.

But the effects I get when ChucK and the Motu act together are really weird. If I try some other number than 8 with --out8 (I've seen this in earlier experiements) I get stuff like identical output on all dac outputs on the box (even though I am only outputting on, say dac.chan(2) in the ChucK app) or every second or third channel, with or without mangled sound like in the example above.

One thing I wanted to try but didn't find out how was to change to bit resolution - I can change the sample rate with --srate but I don't see how to change to using 8 bits or floats. The reason I wanted to try this was that changing the sample rate didn't help.

Yeah, I thought I remembered you ran OSX; that shouldn't really affect this. I just picked Audacity as it's free and cross platform so it's a good example but yes, I heard that the OSX version is lagging which is annoying as it's meant to be inspired by Soundforge which just so happens to be *the* audio app that OSX needs. Sigh. Oh, well it once again turns out we can't have it all and Live is great anyway.

So... if it works in Live this is has to be a ChucK issue, or maybe a MOTU one or possibly a RTAudio one. It's a bit strange to me that the outputs would switch depending on how many you use. I can't imagine that's something that RTAudio would do. I also can't imagine that bit-depth or rate would affect matters... and on top of that I don't think ChucK can switch bit-depth. Internally bit-depth will always be double floats, I think ChucK depends on the soundcard to set bit-depth for the final output.

Erm, I'm a bit at a loss here. My next step would be reporting this to the list as I think RTAudio's maintainer (I think that's Gary Scavone, from memory?) is on there. There may be some issue with the Motu. Just to make sure; you did verify that you are using the latest drivers and that there have been no firmware updates?_________________Kassen

I seem to be able to use the first mic input (tried it with my guitar) by specifying --adc4 on the command line (I guessed that adc numbers match the dac numbers that I see with chuck --probe).

hmmm, you tried a mic input with your guitar. Does this mean that you plugged your guitar into the mic input? That's not kosher because the mic input has too much gain, the signal will be clipped, which is what the "through ChucK" sample sounds like. Or maybe you were using a mic and have this problem? It's difficult to tell from the way you worded that.

Why not try the miniAudicle and look to see what appears in the input selections? It may be an OS X configuration issue, like you have to select it in Sound of System Settings or something. I know when I use line-in with my guitar plugged into it, I must select line-in in System Settings / Sound.

Maybe that helps? I'm not clear on your problem, but try those things. Cheers!_________________"Let's make noise for peace." - Kijjaz

I seem to be able to use the first mic input (tried it with my guitar) by specifying --adc4 on the command line (I guessed that adc numbers match the dac numbers that I see with chuck --probe).

hmmm, you tried a mic input with your guitar. Does this mean that you plugged your guitar into the mic input? That's not kosher because the mic input has too much gain, the signal will be clipped, which is what the "through ChucK" sample sounds like. Or maybe you were using a mic and have this problem? It's difficult to tell from the way you worded that.

Why not try the miniAudicle and look to see what appears in the input selections? It may be an OS X configuration issue, like you have to select it in Sound of System Settings or something. I know when I use line-in with my guitar plugged into it, I must select line-in in System Settings / Sound.

Maybe that helps? I'm not clear on your problem, but try those things. Cheers!

Thanks for the tips. The guitar through the mic thing actually worked pretty ok, it's when I use the synth in another input (a line one) that I get the problem. Besides, I've been putting my guitar into mic inputs without problems - I've always thought that gits and mics worked similarly in this respect.

Are there input selections in MiniAudicle? I'll have a look there, thanks (I normally stick to the command line).

hmmm, you tried a mic input with your guitar. Does this mean that you plugged your guitar into the mic input? That's not kosher because the mic input has too much gain, the signal will be clipped, which is what the "through ChucK" sample sounds like.

That depends on the exact input. the mic inputs on my own soundcard can take mic (with phantom power if needed), guitar or line signals; balanced or unbalanced though of course there is a need to set a appropriate gain. That's quite kosher, the manual covered this and it can even apply amp and cabinet emulations internally if needed (cute for testing a guitar with no amp around).

This will also depend on the guitar used but a mic input/pre-amp on a external soundcard like a Motu will have a knob for pre-amp gain, hopefully with a few meters. It becomes a different issue with build-in soundcards that only have a mini-jack; those are nice for simple things like a mic for online chatting but not the kind of thing to use for recording guitar if it can be at all avoided. Considering the price-class of the MOTU (basically the same as my EMU) I'd be severely disapointed if that instrument/mic input wouldn't be perfectly capable of making every respectable guitar recordings in this configuration._________________Kassen

Stefan, I dunno, I'm still learning about the levels of various equipment, but I thought that guitars generally had signal levels way higher than mics. When I built my combo mic/guitar amplifier I needed two opamps in series with a total gain of about 1,000 on the cermet mic (the little button type, not a studio type), while the guitar needed only a gain of 50 or so. Maybe studio mics are stronger signal levels, and maybe your soundcard's amplifier is set up for lower gains than I needed.

Yes, the miniAudicle has a graphical pull-down menu for selecting the sound input source in the preferences window. This is really handy because on the Mac I can select either the Apple sound system or SoundFlower for receiving routing from iTunes. Sometimes I am constantly switching the line-in/mic/SoundFlower options on and off in System Settings and also switching the Apple built-in audio / SoundFlower pulldown in miniAudicle to do what I want.

Note that you must restart the virtual machine after making changes to the preferences for them to take effect. Maybe the pulldowns in miniAudicle will help you "see" what the problem is, or what ChucK thinks your system has. Look at the Sound portion of System Preferences also, all your stuff should be listed and available on the input and output pulldowns. Cheers!_________________"Let's make noise for peace." - Kijjaz

@Inventor - tried MiniAudicle. I wish I did this sooner since it's a bit more user-friendly, but I still get the same behaviour.

It would be quite odd if the behaviour was different. The Mini's settings are based on the report from --probe and I believe they only affect the parameters for the VM. The underlying technology is the exact same RTAudio library.

I think it *used* to matter in the case of some soundcards that supported arbitrary sample rates like the RME's. In that case --probe tells us very little and the Mini didn't specify sensible defaults. I believe that has been fixed but I don't own a RME._________________Kassen

Oh, I see what you're saying Kassen, I'm used to using a line-in jack out of poverty and I didn't realize that sound cards could obviously be built to handle all inputs. Thanks, that improves my understanding of the whole situation (and makes me want a dang sound card too, but my setup will do for now. Gotta save up for a move to Texas._________________"Let's make noise for peace." - Kijjaz

I've always thought that gits and mics worked similarly in this respect.

No, but it'll work even when not optimal. The guitar output has quite some voltage level but at a high output impedance. A microphone input expects a low level signal but it has a low input impedance. So what happens is that you more or less short your guitar with the microphone input and that will make the the signal level of the guitar go down into a range more suitable for the mic input. However the guitar has no purely resistive output impedance but more an inductive one, and when you short it the frequency characteristic of the result will differ from what you'll get when you plug it into a high impedance input (it'll loose some of the high end as for higher frequencies the guitar's impedance will be higher resulting in more shorting for high frequencies)._________________Jan

Oh, I see what you're saying Kassen, I'm used to using a line-in jack out of poverty and I didn't realize that sound cards could obviously be built to handle all inputs.

Yes... Clearly there is a difference between a card that's build into a mother board that's maybe a buck or two in extra parts for general usage and a 500$ external card meant for professional applications; that should hardly be surprising. Latency, then number on in and outputs, the quality of the conversion, the type of connector, etc, etc, etc.

Fortunately there is a range of options. For you to record your guitar and voice, then listen to the results on a hi-fi a card like the ones Stefan and me are using will be overkill; you'd be paying for features you wouldn't use. Still, where money allows I think it's a bit of a shame to get a guitar and compose for it, then record it using a plain line-in. I'd suggest looking for a modest external soundcard equipped with two dedicated instrument instrument/ mic inputs with pre-amps. If at some time you budget could stretch to such a investment that might be a thing to consider. That said; creativity is of course far more important then the quality of your soundcard and modest budgets can certainly be a stimulation to come up with creative solutions like your external pre-amp._________________Kassen

Well, i built an amplifier for the guitar, so that should take care of the noise problems. It's not quite the quality of a low-noise souncard amp, but the noise should be unnoticeable. Plus I put a mic on the other line-in channel so now ChucK can receive both guitar and mic from me. I did this so I could do that Peter Frampton thing in real time, like we talked about Kassen. So cool on that, delayed a sound card purchase for a while by using extra parts from around the house._________________"Let's make noise for peace." - Kijjaz

Thanks for the info about mic and guitar inputs, all! Yet another piece of knowledge gained from this marvellous place. The ultralite has those combo XLR/TRS jacks, and reading the manual I understand that the XLR has impedance fitting for a microphone, and the TRS is adjusted for guitars.

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